Typically barrier valves or subsurface safety valves are put in a tubular string thousands of meters below a surface location and operated by one or more control lines. As wells get deeper and deeper a concern has arisen among operators that the control line or lines that are used to actuate the barrier valves or safety valves can be damaged when running in the tubular string. Typically control systems for such valves have a one line or two line system to an actuation piston that operates the barrier valve. A two line system is pressure balanced from the perspective of control line hydrostatic pressure because the lines run parallel to each other to the same depth and have the same hydrostatic pressure in each line. One line systems extend a control line to one side of a piston and the other side is referenced to a pressurized compressible gas chamber or a substantial spring to offset the hydrostatic pressure in the single control line.
Many control systems for barrier or safety valves have focused on mechanisms to ensure failsafe operation in the event of seal leaks of actuation piston seals or in the event of a control line shearing or otherwise failing. In those emergency situations reference lines from the control system to the annulus for example have been used to insure that regardless of the nature of the system component failure, a net force on the actuation piston is applied and the valve or tool goes to its designated fail safe position, which is typically the closed position. Typical of such designs are U.S. Pat. Nos. 7,743,833; 7,434,626; 6,173,785 and 6,866,101. One reference suggests the use of tubing or annulus pressure to raise a workstring to create potential energy in the weight of the string so that when needed to go to a failsafe position the weight of the string can act as kinetic energy to move the tool to the failsafe position upon failure of the control line system to normally operate the took. This reference is U.S. Pat. No. 8,162,066. Also relevant are U.S. Pat. Nos. 8,056,643 and 6,210,807.
FIGS. 1-3 show different positions of a barrier valve using dual control lines 10 and 12 leading to an actuator housing 14 that has opposed compartments 16 and 18 on opposed sides of actuating piston 20. A schematically illustrated actuation linkage 22 is connected to valve member 24 that is typically a ball with a passage 26 through it that is selectively aligned with passage 28 of the schematically illustrated tubular string 30 that typically has a production packer 32. In FIG. 1 the actuating piston is midway in its travel representing a partial alignment of passage 26 with passage 28. In FIG. 2 piston 20 has been pushed uphole with pressure in one of the control lines 10 and 12 applied and pressure in the other of the two control lines removed. Conversely, in FIG. 3 the pressure is applied to the other of the two control lines and removed from the other of the two control lines to get the piston 20 to move downhole to a stop position for a fully open position of passage 26 aligned with passage 28.
As previously explained there are installations, particularly offshore where depths can get to 10,000 meters and beyond and the deep placement of the barrier valve to meet regulations for redundant isolation entails long control line runs that not only slow the tripping into the hole procedure but also present a risk of loss of use of the barrier valve if one or both control lines is damaged when running into hole. The present invention addresses this issue with a system that can operate using annulus or tubing pressure. Cycles of applied annulus or tubing pressure will configure a known shuttle valve to direct the available annulus or tubing pressure to the top side or underside of an actuating piston so that the barrier valve can be actuated between an open and closed position when the available pressure is properly directed and removed. The system can be fully hydro-mechanical. Using check valves the applied pressure connection and the vent connection can be in the same space or one can be in the annulus and the other in the tubing. These and other features of the present invention will be more readily understood by those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.